The Herald (Harare)

9 October 2011

Zimbabwe: Asbestos - When White Is Right

opinion

WHEN young Dr Godfrey Mataka arrived in Zvishavane in 1984 to take up the post of medical director at Shabanie Mine Hospital, he expected the worst.

Dr Mataka's fatalism was informed not only by his youthful learnedness, but also the reality of the danger of asbestos, which was being mined here since the early 1930s.

Shabanie and Mashava mines are producers of white asbestos fibre known as chrysotile.

Asbestos is a generic name of fibres with a magnesium silicate base whose products are used for domestic and industrial purposes including, commonly, roofing and piping.

They are also noted for tensile strength, durability and fire resistance.

But exposure to the fibre leads to potentially harmful respiratory conditions such as asbestosis and cancers.

The working conditions of the 1960s had been so bad without safety standards being observed, all sacrificed on the altar of productivity.

The working environment of the old mills was characterised by high levels of dust.

This background presented a scary prospect: a generation of workers being gnawed away by disease, with some already having succumbed to it.

There was also a geographical extent of the worry: in the surrounding areas of Zvishavane and Masvingo, generations had worked and lived off the mine.

The World Health Organisation estimates that 125 million people in the world are exposed to asbestos at the workplace.

Of these, over 107 000 people die each year from asbestos-related lung cancer, mesothelioma and asbestosis resulting from occupational exposure.

One in every three deaths from occupational cancer is estimated to be caused by asbestos.

In addition, it is estimated that several thousands of deaths can be attributed annually to exposure to asbestos in the living environment.

Expecting a high disease burden, Dr Mataka immediately knew what had to be done.

"I called all workers who I thought were at high risk and examined them. Some of them had been working in the mines for as many as 33 and 45 years."

And he got a pleasant surprise.

"All of them had no problems", associated with asbestos, he said.

Examination of the subjects, which are internationally recognised, objective, scientifically proven and reproducible, include asking the subjects on whether they cough or have difficulty in breathing.

A chest X-ray and vitalograph (which checks for the expansion and contraction of lungs) are also conducted.

"Therefore I had a good baseline and worked on improving the working conditions at the mines," he said.

His early encounter at the mine confirmed one thing in particular: that when it comes to the family of asbestos, white is right.

This type of asbestos mined in Zimbabwe is generally safe and free from the hazards that characterise other types mined like crocidolite, and amosite mined in such countries as South Africa and Australia.

Dr Mataka, who is also the Medical Advisor of the African Associated Mines, explained: "Over and above the magnesium silicate base (that make asbestos), crocidolite and amosite have iron.

"The difference in chemistry is responsible for the behavior of the fibres. Studies have been done testing the three in mice as well as the alternatives."

He pointed out that the studies sought to see the behavior and effects in the lungs; on the admission that all fibres were potentially dangerous.

It was established that while chrysotile was broken down in the lungs within 20 days of introduction into the body, crocidolite and amosite stayed longer for up to 400 days.

This biodegradability, or lack of it, and bio-persistence proved the difference.

The physical characteristics of the fibre account also for its effect in the body.

Chrysotile fibre is curly and short and takes longer to reach the lungs while the other fibres are needle-shaped and manoeuvre fast from the nose to the lungs.

The longer fibre takes in the body, the more harm it causes.

Man-made alternatives to asbestos, which have been championed by some countries, have been shown to stay longer in the body (300-400 days), apart from their structural and usage shortcomings.

Besides, they have not been around for long, explained Dr Mataka, for their effects to be manifest as it takes between 30-40 years for them to.

He fears they could be a time bomb.

The World Health Organisation and the International Labour Organisation which have crafted regulations on the use of asbestos, recognise the safety of chrysotile.

International authorities, such as Dr Davd Bernstein, a toxicology expert based in Switzerland, have explained that chrysotile is safe and mining white asbestos was no more hazardous than mining other dust-related minerals like gold and coal.

Back home, Dr Mataka has made sure that there is a safe working environment and use of chrysotile products and a healthy environment and community around.

"We know the dangers of mineral dust and address the work environment," he begins.

"What is the impact of the work environment on the health and safety of the worker; the environment and community? That assessment has to be done," he stated.

Adding: "We identify a hazard; and we identified mineral dust, rocks and noise. We drew a plan on how we would mitigate the effects of those hazards."

To minimise harmful effects of fibre, workers at Shabanie and Mashava mines are given respirators, while there is a central laundry system as workers' protective clothing is laundered here not at home.

But what sticks out among the contingencies that have been put in place is the system of monitoring the health of workers.

Workers are tested and monitored at entry, during the course of their employ and afterwards.

Dr Mataka said workers' lungs are examined at intervals of five years, 10 years and every two years after 20 years.

A worker who retires is recalled after every five years.

"We have an extra incentive," Dr Mataka explains, "we provide health care for former workers and their spouses until they die."

This, he said, allowed the authorities to track and record the health status of the workers and possibly their families.

Each worker and former worker has a medical file which is updated.

A recent visit by The Herald showed the thousands and thousands of files which have been updated at regular intervals.

Dr Mataka says that since 1984, he has not recorded a case of asbestos-related cancer.

Twenty cases of asbestosis had been recorded before; and three people had died of smoke-linked cancer.

Rock dust, instead, had been identified as a big problem.

He revels in the findings.

For him, major disasters like those that occurred in Europe are out of the way.

This owes much to the relative safety of chrysolite as to the efforts of authorities to minimise harm.

He explained that in Europe where harmful types of asbestos had been used in the navy to reduce fire damage, many people who had had a stint at sea came back afflicted by disease.

The same goes for South Africa where even mine waste had been used to pave roads, leading to the affliction of many communities.

These countries are now stigmatising asbestos.

However, major chrysotile producers like Russia, China and Canada and Brazil are fighting to keep production motivated much by scientific evidence that points to the safety of chrysotile, and of course, trade.

In fact, it has been pointed out that the issue of asbestos has gravitated from health concerns to the economy as countries lose or win in the light of the battle.

Stakeholders such as Zimbabwe's cement producer Turnall, which uses white asbestos, have said large companies sought to ban asbestos to push to have the market themselves.

Countries pushing for the ban of white asbestos have been sponsoring individuals and organisations to decampaign the fibre, ostensibly on health grounds.

"Perception is the only problem now," says Dr Matake, as chrysotile has proved safe.

"In fact, had I my way I would minimise the tests we have been carrying out regularly for years now as they always produce the same result. They might even prove dangerous themselves," he said, referring to prolonged exposure to chest X-rays.

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